He's wearing the classic helmet of a centurion, head bristle side-to-side....

contrary to popular belief, centurions were not considered "noncom sergeants" but actually the equivalent of junior field officers...the century was usually between 80-100 men somewhat corresponding to a modern army's company...

You can tell he is a centurion by his transverse crest. Strange he would be in articulated armor, tho. Not normally an officer's choice of armor. As far as the rest of his his kit, the helmet is a spun bowl, not hammered as would have been done originally.